"Replication" refers to the process of manufacturing optical storage media (I.e.: DVD or CD) from raw materials. Lemon recommends this production method for runs of CD of 500 and above for several reasons:
* Replicated CDs are more reliable
* They are of retail quality
* Due to economies of scale and the less labour-intensive nature of their manufacture, replicated CDs are less expensive to produce.
Raw polycarbonate is fed into the barrel of a hydraulic press while under heat where it is pressed into a metal stamper and allowed to cool. Once pressed and cooled, the disc is removed and the centre hole is punched out thus creating the clear plastic part of the disc.
After the metallic layer is applied to the clear blank substrate the disc goes under a UV light for drying and it is ready to go to press. To press the CD first a glass master is cut using a high-power laser on a device similar to a CD writer. This glass master is a positive master. After testing it is used to make a die by pressing it against a metal disc.
The die then becomes a negative image: a number of them can be made depending on the number of pressing mills that are to be running off copies of the final CD. The die then goes into the press and the image is pressed onto the blank CD leaving a final positive image on the disc. A small circle of varnish is then applied as a ring around the centre of the disc and a fast spin spreads it evenly over the surface. The disc can then be printed and packed.
